Quick-acting clamp



#V/ mmf, o, 1mm s mi? 4 VW V/ 5 MMA. f 2. l@ N e 0 m am f w# w wry T 6 BA E D.. A. m w N L O C O m m M m m o A M H C d vl e D. w, u F H March 20, 1951 Patented Mar. 20, 1951 QUICK-ACTING CLANIP Howard D. Houghton, West Los Angeles, and

Theodore A. Woolsey, Pasadena, Calif., assignors to Marman Products Company, Inc., Inglewood, Calif.

Application March 20, 1946, Serial No. 655,648

Claims.

This invention relates to a toggle linkage and to a quick acting clamp employing a novel type of toggle linkage in its operation.

There has long been a need in testing laboratories and the like for a simple, quick acting clamp for application to hose connections, etc., which must be attached and removed frequently in the course of the test work. In such work it is usually necessary to set the clamps to certain predetermined hoop tensions and to have such values the same every time in order to properly correlate the test results. This can, of course, be accomplished with the simple, Well known screw type clamps, but it necessitates the use of torque indicating wrenches, which is inconvenylent and time-consuming.

'The clamp of the present invention solves this problem through the use of a toggle linkage which incorporates in one portion of the linkage a resilient means which comes into play upon closing of the toggle to apply hoop tension in a degree determined by an initial setting.

Since various materials, siries, and test requirements call for different hoop tensions, the toggle linkage incorporates means for varying the initial setting to produce any desired tension upon closing of the toggle.

It has been found that difficulty is experienced ln initiating the locking action of a toggle linkage which incorporates an unrestrained resilient means because its resistance begins to build up as soon as the links are moved toward each other. An important feature of the present invention isthe vprovision of means to pre-load or confine the resilient means so that it does not come into vaction until the actuation of the toggle is almost complete. The initial loading is then increased to the desired value by the final portion of the movement of the toggle to locking position. Another desirable characteristic of a quick acting clamp is ready removability, and the invention contemplates a construction in which at least one link of a toggle is instantly engageable or disengageable with a portion of a clamping band without sacriiicing strength or dependabiity of engagement.

An additional feature of the invention is the provision of a convenient and durable attachment means on a clamping band, for engagement with a toggle link, which is easy to assemble and cannot be readily displaced.

Other features and advantages of the present invention will become apparent as the description proceeds.

' In the accompanying drawing. which shows 2 the presently preferred embodiment of the invention:

Figure 1 is a side elevational View of a quick acting clamp incorporating the novel toggle linkage in its open, disconnected position;

Figure 2 is an end elevational view of the clamp of Figure 1;

Figure 3 is a side elevational view similar to Figure l, but showing the clamp in position about a hose and hose fitting, preparatory to initiating the toggle action;

Figure 4 is a view similar to Figure 3 but showing the toggle and clamping band in locked position; and

Figure 5 is a sectional view on line 5-5 of Figure 1 illustrating the manner of locking the clamping band to its attachment means.

The principal features of construction of the invention are shown in Figure 1 in which the clamping band I0, of flexible material such as stainless steel, is provided With attachment loops I2, I4 at its ends, formed by folding back the extremities and welding them to the intermediate portions of the band as indicated at I.

A compression link, generally indicated at I8, includes a T-shaped member having a crosshead 20 and a threaded shank 22. The crosshead is surrounded by a split bushing 24 to increase its diameter and is journaled in loop I4, with the shank projecting through an opening 2S formed in the loop. n

A trunnion, or anchorage, 28, has a centrally bored passage by means of which it is mounted on the shank of the compression link for longitudinal movement, the outward limit of which is determined by the adjusted position of threaded abutment 3Elwhich, in the presently preferred form, is a self-locking nut. A Vcoil spring 32, of square cross-section wire, encircles the `shank and engages the trunnion. The nut 34 constitutes an adjustable abutment for the inner end of the spring and, by adjusting it outwardly, it is possible to precompress the spring to any ldesired value, since the trunnion 5 is in engagement With abutment 30. The nut 36 may then be tightened against nut 34 to lock it in adjusted position.

The tension link 38 is channel shaped in cross-section and is provided With co-axial bearings 40 carried on bosses 42 extending laterally from the trunnion 28, Hooks 44 are formed in the side walls of the link at its opposite end for engagement with the attachment vmember 46 carried by loop I2.

The attachment member, `as best shown in Figure 5, consists of a cylindrical pin 46, provided With a central annular depression or groove 48 and with coaxial bosses 50 of reduced diameter extending from each end. The length of the larger portion of the pin substantially corresponds with the width of the band, the bosses extending therebeyond for engagement with the hooks 44 of the Ytension link.

In order to prevent accidental displacement of the pin, a depression 52 is formed in the material of the loop I2, for engagement in the annular groove. This depression may be merely a dimple or it may be a groove extending a substantial distance around the periphery of the loop.

The manner of applying and locking the clamp is illustrated in Figures 3 and 4. In the former gure the band il] has been placed about a hose 54 mounted on a pipe or tube 56. The hooks 44 have been brought into engagement with bosses 50 and the toggle is ready to be closed and locked. The rst step is to manually urge the loops toward each other to shorten the base of the toggle. The apex of the toggle is then moved clockwise, as indicated by the arrow in Figure 3. Since the initial distance from the axis of the boss 42 to the axis of boss 56 when engaged in hook 44 is less than the sum of the distance from the axis of boss 42 to the axis of cross-head Z plus the distance from the axis of cross-head 2G to the axis of pin 50 in the clamping position, the swinging of the toggle will produce tension in link 38 and compression in link i8. The only yieldable member in the combination is the spring 32 and consequently it will be axially shortened, as indicated in Figure 4, and the trunnion 28 will move i' inwardly away from abutment 36, so that the distances mentioned above will be substantially equal.

The relative location of the parts is such that the axis of cross-head 2D will pass over the line joining the axes of bosses 42 and 59 in the nal phase of the movement so that the toggle will be rmly locked in the clamping position. This is` readily apparent in Figure 4.

The position of abutment 3d determines the nal compression load in spring 32 and thus the hoop tension in band l0. Lf the outward movement of the trunnion is unrestrained there will be no preloading of the spring and it will be necessary to start overcoming its resistance while the toggle is still relatively open and the mechanical advantage is poor. However, by providing abutment 3G and preloading the spring to just slightly less than its nal loading in the clamped position, this difliculty is overcome and the resistance of .the 4spring is met only when the mechanical advantage is very goodA f t will be obvious that the toggle linkage, as an article of manufacture, may be applied to various types of clamps other than the one shown by way of example, and that provision may be made for a quickly releasable connection at the end of either of the links, or both, if desired. rIhe shape of the link 3B and the provision of the attachment hooks 44 in the side walls produces a high strength weight ratio since the loads are taken in tension and shear, rather than in bending. It will be apparent to those skilled in the art that various changes and modifications may be made in the construction and arrangement of the parts as shown in the preferred arrangement, and it is intended that all such changes and modications shall be encompassed within the scope of the following claims.

We claim:

1. A quick acting clamp comprising: a flexible band adapted to encircle an element to be clamped; a loop formed on a first end of said band provided with an opening therethrough normal to the axis of said loop; a T-shaped link having its head disposed in said loop and its shank extending through said opening; a channel shaped link pivotally connected at one end to the free end of said rst mentioned link and provided with hook formations in the side walls of the channel adjacent to the other end thereof a loop formed on the second end of said band; and a cylindrical pin mounted in said loop and extending laterally beyond said loop on both sides thereof; the hook formations on said channel shaped link being adapted to engage the laterally extending portions of said pin.

2. A quick acting clamp as claimed in claim l; in which said pin and said second mentioned loop are provided with interengaging detent formations to prevent accidental disengagement of said pin from said loop.

3. A quick acting clamp as claimed in claim l; in which said pin is provided with a substantially centrally located annular groove and a portion of the material of said loop extends into said groove to prevent accidental disengagement of said pin from said loop.

4. A quick acting clamp, comprising: a exible band adapted to encircle an element to be clamped; a channel-shaped tension link having one of its ends adapted to be releasably connected to one end of said band; a compression link having one of its ends pivotally connected to the other end of said band; a trunnion slidably mounted on said compression link; an abutment near the free end of said compression link to limit outward movement of said trunnion; a second abutment adjustably carried by said compression link inwardly of said rst abutment; a coil spring coaxially mounted to said compression link between said second abutment and said trunnon and normally urging said trunnion outwardly of said compression link; and means for pivotally connecting the free end of said tension link to said trunnion, whereby said tension link can be pivotally moved to a position in which said compression link is embraced by the said walls thereof as the end of said clamping band attached to said compression link is moved toward the opposite end of said band to radially constrict the latter about the element to be clamped, thereby compressing said coil spring which thereafter acts to create a predetermined hoop tension in said band.

5. A quick acting clamp, comprising: a exible band adapted to encircle an element to be clamped; a loop formed on each of the ends thereof; a cylindrical pin mounted in one of said loops and extending laterally beyond the same on both sides thereof; a channel-shaped tension link having one of its ends adapted to be releasably connected to the laterally extending portions of said pin; a T-shaped compression link having its head disposed in the other of said loops and its shank projecting through an opening formed therein; a trunnion slidably mounted on said compression link; an abutment near the outer end of said compression link to limit outward movement of said trunnion; a second abutment formed on said compression link inwardly of said irst abutment; resilient means mounted between said second abutment and said trunnion and normally urging said trunnion outwardly. 1*of ,said

s compression link; and means for pivotally connecting the free end of said tension link to said trunnion, whereby said tension link can be pivotally moved to a position in which said compression link is received within said tension link as 5 the end of said clamping band attached to said compression link is moved toward the opposite end of said band to yradially constrict the, latter about said element.

HOWARD D. HOUGHTON. 10 THEODORE A. WOOLSEY.

REFERENCES CITED The following references are of record in the 15 le of this patent:

Number Number France May 6, 1927 

